Huge 400-foot tsunamis once washed over Mars

Several billion years ago, Mars had a vast ocean that may have harbored some giant waves.

Mars is a barren, desert planet today, but some 3.4 billion years ago it hosted a mammoth northern ocean. Now scientists have uncovered evidence that this ancient Martian ocean would also have been the premiere place in the solar system to hang ten — that is, if you were a surfer with a death wish. The waves on Mars would have given a whole new definition to the idea of big wave surfing.

According to calculations, Martian waves may have reached 400 feet in height, absolutely crushing shorelines and spreading debris and sediment for hundreds of miles inland. The discovery could help to explain why scientists have had trouble finding evidence of a coastline in the geology of modern Mars. The coastline got obliterated by mega-waves.

“Imagine this enormous red wave coming towards you, up to [400 feet] high,” said Alexis Rodriguez, lead researcher on the study, to Nature. “It would have been pretty spectacular.”

Such a tsunami might remind those who have seen the movie "Interstellar" of Miller's planet, a fictional ocean world in orbit around a black hole, which also harbored giant waves.

The giant waves on Mars wouldn't have been caused by the gravity of a black hole, though. They would have been caused by large asteroids crashing into the ocean. Researchers found evidence of these catastrophic events using imagery from several Mars-orbiting spacecraft, which showed geological formations consistent with the crash of a giant wave against a shoreline.

One such feature looks as if an enormous wave had rushed up onto the edge of some Martian highlands. Several boulders as big as 10 meters across could be identified, which could have been dropped by an enormous wave. There is also visual evidence of channels that would have been cut as the water drained back into the ocean.

An exciting consequence of these Martian mega-tsunamis could be that they may have inundated large inland craters with water, essentially forming lakes where life might have been able to evolve and thrive. These craters might make ideal places to look for evidence of life during future missions.